From another board:
 Hey guys, I want to tell you all a sad story.

Please see this link:

https://imgur.com/a/ADsbSYI

This is a lesson I guess I had to learn, the hard way.  This is pitting or etching in my Service Rifle barrel.  This was the best SR barrel I have had to date, and it was the best build I have ever done on one of my personal rifles.

I built an upper for Sean Morris in 2019, and he went on to win the Service Rifle Championship, and was 3rd overall at NRA.  I had been feeling pretty good about my builds, and this barrel got me 5th at OBR in 2020, and a personal best in OTC with a 793.

Then, the 'Rona got us and I got lax on my shooting and cleaning.

At the Lacrosse match, at the end of August last year (2020), I was struggling with my 6mm ARC - I had a (relatively) bad string/match, and wanted to see if I could eliminate some variables.  So, I pulled out the ol' Workhorse.  And the horse worked - I lay down and shot a 199.  At that point I knew it wasn't me or the conditions - and started looking into what was wrong: brass.  But on that 6mm, it's a different story.

Anyway, I put the rifle away, stuffed it in the safe, and forgot about it until last month.

After cleaning I wanted to check the gas port.  To my horror, I saw these squiggly marks throughout the barrel.  It was intermittent, but it was there.  I decided to shoot a match with it anyway (the Sierra Cup).  All in all, it shot pretty well.  I can chalk up my scores to the conditions and my condition - I had not lay down and shot or practiced prone since that August match.

But the damage was done. 

Most likely, the barrel would be OK - I could shoot it - but my confidence in it is gone.  And that really sucks, because it shot so well I wanted to run it til it puked.  And so it has, at about half life.

The lesson here is: clean your rifle.  I preach it, I yell, scream, and holler it from on top of the mountain, and then I failed to follow my own advice.

We have been seeing this occasionally, and what we have figured out is that it is a reaction from moisture and the powders that are being used.  It's not delamination of the material, or a breakdown in the microstructure - it's corrosion.  In stainless steel barrels this is how it shows up, and not as red-rust (not normally).  The most common culprit of this is from Bore-Tech eliminator.  While it is a fine product, it is a 95% water-based solvent, and has to be neutralized with another solvent like Hoppe's #9, or chased out with an oil.  WD-40 is good for this because it is "Water Displacement, 40th try", and should blow the moisture out of the barrel, if followed by a neutralizing agent like Hoppe's.

So, I screwed up.  And mostly, it's a head game.  So I get to eat crow, proclaim my fealty, and buy a new barrel, when this one was only at half-life, and was the best one I'd ever had.

Please clean your rifles!

Best,

Brady

why need or want a 95% water based solvent?

A very interesting thing about Stainless Steel that is rather counter intuitive, it needs to be exposed to air or it will corrode severely..


'Stainless steel requires a supply of oxygen to make sure that the passive layer can form on the surface. In very tight crevices it is not always possible for the oxygen to gain access to the stainless steel surface thereby causing it to be vulnerable to attack.'

https://www.montanstahl.com/blog/corrosion-on-stainless-steel/


Found this out working on Sailboats.

We have been seeing this occasionally, and what we have figured out is that it is a reaction from moisture and the powders that are being used.  It's not delamination of the material, or a breakdown in the microstructure - it's corrosion.  In stainless steel barrels this is how it shows up, and not as red-rust (not normally).  The most common culprit of this is from Bore-Tech eliminator.  While it is a fine product, it is a 95% water-based solvent, and has to be neutralized with another solvent like Hoppe's #9, or chased out with an oil.  WD-40 is good for this because it is "Water Displacement, 40th try", and should blow the moisture out of the barrel, if followed by a neutralizing agent like Hoppe's.

I have BoreTech carbon and copper removers, but haven't used it yet.  Am using another product line/combo, at least for now.  I haven't used the Eliminator, but I know a couple of buddies who do 

Is the "fix" for what happened to the guy then clean after shooting?  It mentions reaction to powders.  Or would mitigation be neutralizing after the last cleaning session? 

I've read where many folks neutralize after using some solvents.  I thought I recall some folks mentioning not wanting to leave in Hoppe's #9.  I have used Hoppe's #9 for many years, but mostly for my ARs.  Haven't used Hoppe's on my bolt gun for a while.  Not really concerned about my ARs.  Not really for my current bolt gun, but I will be when I rebarrel this current gun or go with a custom action and barrel combo. 

Even when I used Hoppe's for my other long guns, I had been running a dry patch after the last solvent.  And then run a patch with Ballistol.  Wasn't really sure if it was needed, but what I was told by a "trusted friend" early on and kept going with it.  Lately, my ARs don't get cleaned that often anymore.  My bolt guns get different treatment though. 

Does anyone use the G96 product line for bore cleaning?

http://www.g96.com/products/military-approved-products/military-approved-synthetic-clp-gun-oil/

With Mil-Spec approval, it seems to have the blessing of the US Army. Plan to use this with Ramrodz swabs.

If it says "environmentally friendly" it most likely contains water.